1. Technical Field
The present invention relates to an ink set for ink jet recording and to a recording apparatus.
2. Related Art
Ink jet recording apparatuses record images and characters by discharging very small droplets of ink through the nozzles of an ink jet recording head. An ink jet recording apparatus has some channels through which the ink flows, e.g., those for supplying the ink from an ink container, which contains the ink, to the ink jet recording head and those formed in the ink jet recording head to deliver the ink to nozzle openings (holes of the nozzles). These ink flow channels are often so small that various problems can occur; for example, these ink flow channels are likely to become clogged with the ink jet recording ink.
Examples of known solutions to such problems include removing the blockage in the ink flow channels and the nozzles and related defects by applying cleaning liquid or maintenance liquid to the surface of the nozzles to keep the surface moist or by passing cleaning liquid or maintenance liquid through the ink flow channels.
For example, JP-B-6-8437 and JP-B-8-30200 are intended to provide maintenance liquids for ink jet recording. These maintenance liquids are advantageous in the following ways: an ink system that includes ink flow channel and nozzles can be quickly clear of ink; maintenance liquid residue has no negative effects while the ink system is stored for a long period of time; the ink system can be quickly refilled with ink. JP-B-6-8437 discloses a maintenance liquid for ink jet recording that contains (a) at least one polyhydric alcohol selected from ethylene glycol, diethylene glycol, triethylene glycol, and propylene glycol, (b) at least one alcohol selected from methanol, ethanol, n-propanol, and isopropanol, and (c) water. JP-B-8-30200 also discloses a maintenance liquid for ink jet recording, and this maintenance liquid contains (a) at least one alcohol selected from methanol, ethanol, n-propanol, and isopropanol, (b) an anionic surfactant that has a functional group selected from —SO3M, —OSO3M, and —COOH (M: H, Li, Na, or K), and (c) water.
JP-A-4-261476 discloses a cleaning liquid for ink jet printers, which contains an aqueous medium and at least one specified compound so that the cleaning liquid can have excellent detergency and good antifungal and antibacterial effects.
JP-A-11-263021 discloses an ink jet printer used with a recording liquid based on an aqueous pigment. The ink jet printer is equipped with a head-cleaning liquid that removes thickened ink that accumulates on the surface of nozzle plates and the cap for the nozzles as water in the aqueous pigment-based recording liquid evaporates. As a result, the ink jet printer can be free of poor discharge, dirty nozzle plates, poor sealing, and other problems associated with adhering thickened ink.
JP-A-11-263022 discloses an ink jet printer. The ink jet printer is equipped with a recording liquid based on an aqueous pigment and a head-cleaning liquid. The recording liquid contains a dispersant and a fixing agent, and at least one of the dispersant and the fixing agent is an anionic water-soluble polymer that contains a carboxylic acid salt or an anionic surfactant that contains a carboxylic acid salt. The head-cleaning liquid is an alkaline solution of a nonionic surfactant and/or an anionic surfactant in water at a pH of less than 11. As a result, the ink jet printer can be free of poor discharge, dirty nozzle plates, poor sealing, and other problems associated with adhering thickened ink.
JP-A-2000-109733 is intended to provide an aqueous ink for ink jet recording and maintenance liquid and a method for maintaining an ink jet recording apparatus used with the ink. The aqueous ink for ink jet recording, according to the publication, has excellent dispersion stability, does not clog up nozzles, is unlikely to bleed at high concentrations, and, in particular, is highly resistant to water and washing. The disclosed aqueous ink composition contains an aqueous medium composed of at least water, pigment-colored resin particles contained in a resin (A) that has a carboxy group, and a base (B) and also contains a constituent (C) that forms cross-links with the resin (A).
JP-A-2000-328093 discloses an aqueous cleaning liquid for cleaning the printhead of ink jet printers. The aqueous head-cleaning liquid contains a silicone-based antifoam so that the head-cleaning liquid can be very unlikely to foam, have excellent detergency and antifungal and antibacterial effects, and should not clog up the printhead used therewith.
JP-A-2002-105500 relates to a cleaning liquid for ink jet printers and is intended to provide a cleaning liquid for ink jet printers that easily resolves problems associated with clogged nozzles by its excellent detergency. The disclosed cleaning liquid contains at least a water-soluble hydroxycarobylic acid salt, limonene, and a surfactant.
These cleaning liquids and maintenance liquids are, however, disadvantageous when used to clean ink flow channels of ink jet recording apparatuses. The user tries to remove the cleaning/maintenance liquid and refill the apparatus with the recording ink to resume recording; however, the cleaning/maintenance liquid cannot be easily removed, and this causes several problems. For example, cleaning/maintenance liquid residue in the recording ink may affect the quality of recordings, and bubbles left after incomplete refilling may block the ink flow channels. Furthermore, replacing the recording ink with the cleaning/maintenance liquid may cause ink residue to adhere to the walls and elsewhere inside the ink flow channels, and such adhering ink residue may clog up the ink flow channels. The issue of clogging becomes particularly significant when the recording ink contains a pigment as coloring material and a resin as fixing agent.